We were very curious to find out what an (international) embryologist actuallydoes. What goes on behind the scenes, and can she give us some inside information on how embryos are handled?

Enjoy! 🙂

Please introduce yourself and tell us what a typical day looks like for you?

My name is Linda. I am 37 years old and I have worked as an embryologist since 2007. I graduated from the Faculty of Science at Charles University in Prague.

The work in the lab begins at 6:30 am. First, we check the embryonic development and select embryos for fresh embryo transfer, which will be vitrified or further cultivated. Then we enter their data in a computer program. Operation in the theatre begins around 8 am. First, egg collection takes place. We search for eggs in test tubes from the puncture. After egg collection, we inform the patient about the oocyte collection and agree on the type of fertilization, number of embryos for embryo transfer and other procedures. Fertilization of eggs begins around noon. Embryo vitrification occurs during the day and transfers take place in the morning and afternoon. Later in the afternoon, preparations are made for the next day.

How did you get into this line of work?

I came across the position as embryologist completely by chance. I responded to a job advertisement after I completed my studies.

What do you like most about being an embryologist?

I like the feeling when we succeed in helping a couple that wishes to have a baby.

Do you get to find out whether a patient got pregnant?

Yes, we find it out.

What kind of protocols are in place to ensure that a patients’ material (egg, sperm, embryo) are matched-up to the correct patient?

All samples that enter the fertilization process are always labeled with the names of the patients.

In your lab, is regular IVF still used or do most eggs get fertilized using ICSI?

It is possible to use IVF fertilization, but we use ICSI in almost 100% cases. The success rate (Mrs. FC edit: this refers to the fertilization rate) with IVF is about 50%, but it may happen that nothing at all is fertilized. The success rate with ICSI is 80-85%. Couples who choose IVF fertilization wish to have at least something done “naturally”. Other procedures of fertilization include PICSI and IMSI.

Can you describe how you grade embryos at the different stages?

Embryos are evaluated on a daily basis by the number of cells, their size, location, and fragmentation rate. For blastocysts, the evaluation is performed according to the Gardner rating system. (Mrs. FC edit: See this page for a quick overview of the Gardner rating system). Embryos are evaluated every morning around 7 am.

What percentage of transfers are 3-day embryos as compared to 5-day embryos?

In most cases, embryo transfer is carried out on day 5 of the cultivation.

How is it decided to call in a patient for a day 3 transfer instead of a day 5 transfer? Is there a certain cut-off of? Does the embryologist make the decision (of when) to transfer, or is it left to the doctor?

We arrange the day of embryo transfer with the patient after egg collection. Some patients wish to have embryo transfer on a specific day. When they leave the choice to the laboratory, we decide in the morning during evaluation of embryos according to the quality and number of embryos. The transfer may take place on the 2nd – 5th day of cultivation (in rare cases even on day 6). In case of a lower number of embryos we usually transfer earlier than on day 5, provided the patient agrees with it.

In your lab, what percentage of fertilized eggs develop into blastocysts? And on what day do you see the largest drop in how many still survive?

Approximately 25% of embryos reach blastocyst stage. It is not possible to predict how many embryos will survive to the 5th day. There is a natural selection and some couples have more embryos that survive and other couples fewer.

How long do you give embryos a chance to make it to blastocyst?

The maximum duration of cultivation we do is 6 days.

What milestones does an embryo need to achieve in order for you to freeze it? Do you freeze embryos that don’t make it to blastocyst stage?

Embryos for freezing are embryos that correspond to a given day of cultivation and are superfluous compared to embryos that are best suitable for embryo transfer. We freeze all stages of embryos that look good, not just blastocysts.

How long can embryos be stored in cryo? Is there a decline in successful thaws, depending on time in storage?

Maximum storage time is not defined. Storage time does not affect embryo quality. The oldest frozen embryo in our clinic is from 2011, when the branch GENNET Archa was established. But I know that embryos from 2008 were thawed and everything was fine.

Are there any benefits to storing 1 embryo per straw (vs 2)?

The fact whether one or two embryos are frozen in the straw has the advantage that if two embryos are frozen together, then both embryos must be thawed. When the patient requires only one embryo for embryo transfer, there is always a question of what to do with the second embryo. In order to freeze it again it must be of excellent quality, but even then there is no guarantee that after further freezing and subsequent thawing it will be suitable for transfer.

Can (leftover) embryos be donated to science or to other couples?

Embryos can be donated. A couple that wishes to donate embryos must undergo a series of examinations. Embryos can be used for research purposes as well, if a patient wishes to do so.

What, in your opinion, do you see as the biggest improvement(s) in IVF in the last years, and what do expect will be the most important new development in the near future?

Let us see what the future brings. I am very curious myself as to what to expect for progress and innovation in the field of embryology.

Big thanks to Linda from GENNET for answering all of our questions. I think we learned a lot of interesting things from these interviews, one of them being that many Czech’s are into short but sweet answers ;-). But all kidding aside, it’s awesome to get a closer look at how an IVF clinic works.

Some of you may still be interested in a 10% off coupon from GENNET that we shared in Part I of the Interview series. I still have a few left, so if you are looking to save a bit of money, feel free to send me an email or leave a comment!

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Mary Gordon

Queen T

I’m really happy to see the part about storing the embryos in different straw before my treatment. I never thought of that. We only want to transfer one at a time and it would break my heart if the other could not be refrozen.